1. Field of the Invention
The present invention relates to a process to produce a semiconductor device, in particular, those having electrodes formed on a semiconductor layer.
2. Background Arts
Electronic semiconductor devices inevitably provide ohmic electrodes on a semiconductor layer. A Japanese Patent Application with a laid open number JP-H05-275373A has disclosed a process for a semiconductor device where the process first forms an ohmic electrode on a semiconductor layer, covers the ohmic electrode with an insulating film, forms an opening in the insulating film in a portion on the ohmic electrode, and finally forms an interconnection connected to the ohmic electrode by plating. The plated metal not only fully covers the opening in the insulating film but extends on the insulating film in portions adjacent to the opening.
When the plated metal in a bottom edge thereof has an overhung side surface, namely, an undercut against layer beneath the plated metal, an insulating film or a passivation film covering the plated metal is hard to be in contact to a deep end of the overhung plated metal, which may degrade long-term reliability of the plated metal, and the semiconductor device providing such plated metal and the passivation film. The present invention is to provide a solution to enhance the coverage of the overhung metal with the insulating film.